Edible film containing food acid

ABSTRACT

An edible film composition for delivering an active agent to the oral cavity, the composition comprising a water-dispersible film composition comprising a cellulose ether and a starch, and a food acid.

The present invention relates to an orally administrable film fordelivery of a food acid, and optionally other active agents, to the oralcavity.

Edible films that are rapidly disintegrating in the oral cavity areknown in the art. These films are used to deliver breath fresheningagents, flavourants, pharmaceutical active agents, nutrients and thelike. They generally contain water-soluble polymers and otherconventional excipients such plasticisers and emulsifiers. Selection ofparticular polymers and other excipients are based on considerations ofthe film properties. Thus, it is conventional to employ a water-solublepolymer that is capable of forming robust films with good mechanicalstrength; plasticisers are chosen to provide softness and pliability tothe films, whereas emulsifiers are used to ensure that films may be castfrom a solution in an acceptably uniform manner.

However, applicant is not aware of prior art teaching the selection offilm ingredients based on a consideration of their interaction withactive agents; essentially the art silent as to film ingredient-activeagent interactions and the role they play on film stability and activeagent delivery. The skilled person is left with the impression that ithas latitude to select film ingredients independent of the nature of theactive ingredient to be delivered.

In recent times, the trend has developed for edible films that aremulti-functional. That is, it is not only desirable to deliver singleactive agents, such as flavours, from edible films, it is also desirableto present the consumer with other sensations in the mouth as a resultof consuming film. In particular, it is desirable to deliver a tartnessor sourness and a mouth-watering sensation. Such a mouth sensation maybe achieved with food acids.

However, there are considerable technical challenges associated withincorporating food acids into edible films. In particular, applicantfound that a film's mechanical strength was compromised by adding foodacid to the film. It was also observed that the films displayed poorhygroscopic stability making them difficult to manufacture and store,and unattractive to consumers. For example, in some cases the films whenplaced together tend to stick together to form a gum.

It is highly desirable to provide films that can deliver a tartness orsourness and mouth-watering effect and which are mechanically strong andhygroscopically stable.

The applicant has now surprisingly found that by combining certain typesof film-forming polymers it is possible to form edible films thatrapidly dissolve or disintegrate and disperse in the mouth and whichsolve the problems referred to above.

Accordingly, the invention provides in a first aspect an edible film fordelivering an active agent to the oral cavity comprising awater-dispersible film-forming material selected from a cellulose etherand a starch, and a food acid.

The food acid may be selected from the group consisting of citric acid,malic acid, glacial acetic acid, anthranilic acid, tartaric acid, tiglicacid, ascorbic acid, benzoic acid, tannic acid, succinic acid, adipicacid, fumaric acid and lactic acid.

These food acids, are preferably employed in edible film formulations atlevels of at least about 8% by weight based on the dry weight of theedible film composition, more preferably from about 8% to about 25% byweight. Dry weight according to the present invention refers to theweight of all of the edible film composition components without addedwater. The above-mentioned levels of food acids are preferred in orderto give a desirable tartness or sourness impression and to achieve adesirable mouth-watering effect. Whereas, it may be possible toincorporate lower amounts of acid into the films and thereby avoid anyinstability problems associated with the films, one cannot reliablyachieve the desirable mouth-sensations aforementioned.

The acid may be incorporated into the films in encapsulated form. Inthis manner, high levels of acid (even higher than the amountsaforementioned if desired) may be incorporated without any detrimentaleffects on the physical properties of the film, however in manyapplications, the acid has to be released immediately into the mouth asthe film disintegrates in order to provide an instant mouth-wateringeffect. If the acid is encapsulated, the onset of the mouth-wateringeffect is delayed, in a manner dependant on the release of the acid fromthe capsule.

Cellulose ethers for use in the present invention may be any of thoseknown materials that are water-swellable, and soluble or dispersible inwater and which can be cast or extruded into films. For a discussion ofthese ethers one can refer to Ullman's Encyclopedia of Chemistry (VCHVerlagsgesellshaft mbH, 1986 revised edition, Vol A 5 at 461 to 488,which is incorporated herein by reference. Preferred materials areselected from the group consisting of methyl celluloses and mixed ethersthereof such as hydroxyethyl methyl cellulose, hydroxypropyl methylcellulose, hydroxybutyl methyl cellulose, ethyl methyl cellulose, andcarboxymethyl methyl cellulose; ethyl cellulose and mixed ethers thereofsuch as ethyl hydroxyethyl cellulose; hydroxyalkyl cellulose ethers suchas hydroxy ethyl cellulose, hydroxypropyl cellulose,hydroxyethylhydroxypropyl cellulose, and carboxymethyl hydroxyethylcellulose; or mixtures thereof.

The hydroxypropylmethyl cellulose ethers are preferred.

The cellulose ethers are selected for their excellent film-formingability, their ability to be plasticised using common plasticisers andtheir ability to be cast or extruded as sheets.

Suitable starches for use in the present invention are any of thoseknown starches or modified starches that rapidly hydrate and disperse ordissolve, and which can be cast or extruded into films. For a discussionof such starches see Ullman's Encyclopedia of Chemistry (VCHVerlagsgesellshaft mbH, 1994 revised edition, Vol A 25 at Ch 2, which isincorporated herein by reference. Starches for use in the presentinvention may be native starches or modified starches known in the artand which are easily hydrated and disperse or dissolve in water. Asstarches there can be mentioned corn starch, potato starch, rice starch,tapioca starch, maize starch, sorghum starch, sago starch wheat starchor sodium starch glycolate; or any native starch that has beenchemically modified, e.g. acid-modified; or mixtures thereof.

The film-forming materials, that is, the cellulose ethers and starchesreferred to above, may be employed in varying amounts depending on thenature of the material, the particular film-forming conditions employed,the desired properties of the film, and the nature of the otheringredients employed in the film. For most purposes however, highamounts of the film formers are desirable, and it is preferred if thetotal amount of film-formers is from 50 to 90%, more particularly 50 to80% by weight based on the dry weight of the composition.

The ratio of cellulose ether to starch may also vary considerablydepending on the disintegration properties sought. Typically one mayemploy 4 parts cellulose ether to 1 part starch. However, this ratio mayvary. For example, if one wants to increase the rate of hydration of thefilm one can increase the starch content; whereas if one wants toincrease the mechanical strength of the film, higher amounts ofcellulose ether are preferred.

The edible film may additionally contain gelatin or pectin. Gelatin orpectin may assist in the hydration of the film when it is placed in themouth. Rapid hydration is important to because customers often associateslow hydration with unpleasant mouth feel. It is preferred if hydrationof films occurs in a matter of seconds, e.g. within 30 seconds, moreparticularly 5 to 10 seconds. Gelatin or pectin may be employed atlevels of up to about 30 wt % based on the dry weight of theformulation.

Edible film according to the invention may contain other, optional,ingredients. For example, the film may contain excipients that assist infilm formation, handling and stability such as emulsifiers andplasticisers. Other excipients may include preservatives, anti-oxidants,colourants and the like. The films may also contain additional activeagents as stated above.

As emulsifiers one can mention lecithin, stearates, ester derivatives ofstearates, palmitates, ester derivatives of palmitates, oleates, esterderivatives of oleates, glycerides, ester derivatives of glycerides,sucrose polyesters, polyglycerolesters, and animal waxes, vegetablewaxes, synthetic waxes, petroleum, and mixtures thereof. Particularlyuseful emulsifiers are lecithin, non-ionic surfactants, such aspolyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylethers, or polyoxyethylene castor oil derivatives with one or morepolyalcohols, or mixtures thereof.

Emulsifiers may be employed in amounts of up to 2% by weight, morepreferably up to 1% by weight based on the dry weight of theformulation.

Plasticisers may be employed in edible film compositions to impartflexibility to the film thereby to increase the ease of handling of thefilm during storage and during use. As plasticisers there may bementioned any of those materials commonly used as plasticisers in ediblefilm technology, in particular polyhydric alcohols such as glycerol,polyethylene glycol, propylene glycol, gycerin, sorbitol, maltitol andmannitol.

Plasticisers may be employed up to 5%, more preferably up to 1% byweight based on the dry weight of the formulation.

Colourants and patterns of colours are attractive to the eye and act asa visual cue to consumers identifying certain products with brandowners. The colouring agents useful in the present invention, includepigments such as titanium dioxide, which may be incorporated in amountsof up to about 5 wt %, and preferably less than about 1 wt %. Colorantscan also include natural food colours and dyes suitable for food, drugand cosmetic applications. These colorants are known as FD&C dyes andlakes. The materials acceptable for the foregoing spectrum of use arepreferably water-soluble, and include FD&C Blue No. 2, which is thedisodium salt of 5,5-indigotindisulfonic acid. Similarly, the dye knownas Green No. 3 comprises a triphenylmethane dye and is the monosodiumsalt of 4-[4-N-ethyl-p-sulfobenzylamino)diphenyl-methylene]-[1-N-ethyl-N-p-sulfoniumbenzyl)-2,5-cyclo-hexadienimine]. A full recitation of all FD&C and D&Cdyes and their corresponding chemical structures may be found in theKirk-Othmer Encyclopedia of Chemical Technology, Volume 5, Pages857-884, which text is accordingly incorporated herein by reference.

As stated herein above, the edible films may contain other activeingredients such as flavourants, pharmaceutical agents and nutraceuticalagents.

The particular flavour ingredients employed depend on the end-use of theedible film. Flavour ingredients may be employed to impart a savourytaste to a food product. However, more preferably the flavouringredients employed are used in films intended for breath-fresheningapplications or for confectionery or cosmetic products, or even toimpart a pleasant taste, or taste-masking effect, to pharmaceutical ornutraceutical preparations.

Flavourants may be chosen from synthetic flavor oils and flavoringaromatics, and/or oils, oleo resins and extracts derived from plants,leaves, flowers, fruits and so forth, and combinations thereof.Representative flavor oils include: spearmint oil, cinnamon oil,peppermint oil, clove oil, bay oil, thyme oil, cedar leaf oil, oil ofnutmeg, oil of sage, and oil of bitter almonds. Also, one can mentionartificial, natural or synthetic fruit flavors such as vanilla,chocolate, coffee, cocoa and citrus oil, including lemon, orange, grape,lime and grapefruit and fruit essences including apple, pear, peach,strawberry, raspberry, cherry, plum, pineapple, apricot and so forth.These flavorings can be used individually or in admixture.

Examples of suitable flavour components include without limitation2-Methyl Pyrazine, Acetophenone Extra, Alcohol C6, Alcohol C8, AldehydeC7 Heptylic, Aldehyde C8, Aldehyde C9, Allyl Caproate, Amyl Butyrate,Anisicaldhyde, Benzaldehyde, Benzyl Acetate, Benzyl Alcohol, BenzylButyrate, Benzyl Formate, Benzyl Iso Valerate, Benzyl Propionate, ButylAcetate, Camphor, Cinnamic Aldehyde, Cis-3-Hexenol, Cis-3-HexenylAcetate, Cis-3-Hexenyl Formate, Cis-3-Hexenyl Propionate, Citronellal,Citronellol, Cuminic Aldehyde, Damascenone, Damascone Alpha, DamasconeBeta, Diethyl Malonate, Dimethyl Anthranilate, Dimethyl Benzyl CarbinylAcetate, Estragole, Ethyl Acetate, Ethyl Aceto Acetate, Ethyl Benzoate,Ethyl Heptoate, Ethyl Salicylate, Ethyl-2-Methyl Butyrate, Eucalyptol,Eugenol, Fenchyl Acetate, Fenchyl Alcohol, Methyl-2-octynoate,2-sec-Butylcyclohexanone, Styralyl Acetate, Hexyl Acetate, Ionone Alpha,Iso Amyl Acetate, Iso Butyl Acetate, Iso Menthone, Jasmone Cis, LaevoCarvone, Linalool, Linalool Oxide, Melonal, Menthol, Menthone, MethylAcetophenone, Methyl Amyl Ketone, Methyl Benzoate, Methyl Heptenone,Methyl Hexyl Ketone, Methyl Para Cresol, Methyl Phenyl Acetate, MethylSalicylate, Neral, Nerol, Para Cresol, Para Cresyl Acetate, Para TolylAldehyde, Phenyl Acetaldehyde, Phenyl Ethyl Acetate, Phenyl EthylButyrate, Phenyl Ethyl Formate, Phenyl Ethyl Iso Butyrate, Phenyl EthylPropionate, Phenyl Propyl Acetate, Phenyl Propyl Aldehyde,4-Methyl-2-(2-methyl-1-propenyl)tetrahydropyran, Styralyl Propionate,Terpineol, Terpinolene, Trans-2-Hexenal, Hexyl Cinnamic Aldehyde Alpha,Oxacycloheptadec-10-en-2-one, Linalyl Benzoate, Cedrol, BenzylCinnamate, Linalyl Cinnamate, Phenyl Ethyl Cinnamate, Para Cresyl PhenylAcetate, Benzyl Salicylate, Hexyl Salicylate, Phenyl Ethyl Salicylate,and Oxacyclohexadecan-2-one.

The amount of flavoring employed is normally a matter of preferencesubject to such factors as flavor type, individual flavor, and strengthdesired. Thus, the amount may be varied in order to obtain the resultdesired in the final product. Such variations are within thecapabilities of those skilled in the art without the need for undueexperimentation. In general, amounts of about 0.1 to about 30 wt % basedon the dry weight of the composition are useable with amounts of about 2to about 25 wt % being preferred and amounts from about 8 to about 10 wt% are more preferred.

In addition to flavourants, the edible film compositions may containsweeteners or coolant materials well known in the art for use in oralcare, or confectionery products.

Sweeteners include both natural and artificial sweeteners. Suitablesweetener include water soluble sweetening agents such asmonosaccharides, disaccharides and polysaccharides such as xylose,ribose, glucose (dextrose), mannose, glatose, fructose (levulose),sucrose (sugar), maltose, water soluble artificial sweeteners such asthe soluble saccharin salts, i.e., sodium or calcium saccharin salts,cyclamate salts dipeptide based sweeteners, such a L-aspartic acidderived sweeteners, such as L-aspartyl-L-phenylalaine methyl ester(aspartame).

As coolants one can mention menthol and derivatives thereof such asmenthol carboxamide, and menthyl lactate.

In general, the effective amount of sweetener or coolant that isutilized to provide the level of sweetness or coolness desired for aparticular composition, will vary with the sweetener or coolantselected. This amount will normally be about 0.01% to about 2% by weightof the composition, based on the dry weight of the composition.

As pharmaceutical agents or nutraceutical agents may be mentioned agentsthat are intended to be placed in the oral cavity to administer a localeffect, or to be absorbed across oral mucosa or open wounds to impart alocal or systemic effect. Illustrative categories and representativeexamples include without limitation:

-   (a) Antitussives, such as dextromethorphan, dextromethorphan    hydrobromide, noscapine, carbetapentane citrate, and chlophedianol    hydrochloride;-   (b) Antihistamines, such as chlorpheniramine maleate, phenindamine    tartrate, pyrilamione maleate, doxylamine succinate, and    phenyltoloxamine citrate;-   (c) Decongestants, such as phenylpherine hydrochloride,    phenylpropanolamine hydrochloride, pseudoephedrine, hydrochloride    ephedrine;-   (d) Various alkaloids, such as codeine phosphate, codeine sulfate    and morphine;-   (e) Mineral supplements such as potassium chloride and calcium    carbonates, magnesium oxide and other alkali metal and alkaline    earth metal salts;-   (f) Laxatives, vitamins and antacids;-   (g) Ion exchange resins such as cholestyramine;-   (h) Anti-cholesterolemic and anti-lipid agents such as gemfibrozil;-   (i) Antiarrhythmics such as N-acetyl-procainamide;-   (j) Antipyretics such as acetominophen, aspirin and ibuprofen;-   (k) Appetite suppressants such as phenylpropanolamine hydrochloride    or caffeine; and-   (l) Expectorants such as quaifenesin.

Additional useful active medicaments include anti-inflammatorysubstances, coronary dilators, cerebral dilators, peripheralvasodilators, anti-infectives, psychotropics, antimanics, stimulants,gastro-intestinal sedatives, antidiarrheal preparations, anti-anginaldrugs, vasodilators, anti-hypertensive drugs, vasoconstrictors andmigraine treatments, antibiotics, tranquilizers, antiphychotics,antitumor drugs, anticoagulants and antithrombotic drugs, hypnotics,sedatives, antiemetics, anti-nauseants, anticonvulsants, neuromusculardrugs, hyper- and hypoglycaemic agents, thyroid and antithyroidpreparations, diuretics, antispasmodics, uterine relaxants, nutritionaladditives, antiobesity drugs, anabolic drugs, erythropoietic drugs,antiasthmatics, cough suppressants, mucolytics, anti-uricemic drugs, andthe like. Mixtures of the drugs and medicaments may also be used.

The amount of pharmaceutical or nutraceutical agent employed will dependupon the particular condition to be treated and the particular activeagent employed as will be appreciated by the skilled person.

Any of the active agents referred to above may be incorporated directlyinto the film forming ingredients to form an homogenous mixture that maybe cast or extruded into edible film. However, interesting deliveryprofiles may be achieved by encapsulating the active agent rather thanmixing it directly with the film-forming ingredients.

Thus encapsulation may be used to deliver any active agent in atime-controlled manner rather than the immediate release that wouldoccur upon disintegration of the film if the active is mixed directlyinto the film.

All manner of technical effects relating to delivery of active agent canbe achieved using microcapsules to encapsulate active agents. Forexample, microcapsules may be multifunctional, that is, there may bedifferent populations of microcapsules containing different activeagents. Furthermore, not only can the populations of microcapsules bedifferentiated in terms of the nature of the active agent containedtherein, the invention also provides that the microcapsules may comprisedifferent populations in terms of the nature of the encapsulatingmedium, thereby to influence the release kinetics of the activeingredients contained in different microcapsule populations.

The present invention therefore provides the formulator withconsiderable latitude to effect release of different active agents ondemand, in a time-dependant manner. This can be particularlyadvantageous in relation to delivery of flavourants The flavourist willhave greater latitude to employ the range of his ingredients palettewith neither concern for the effects certain ingredients shall have theon film's properties, nor concern for possible ingredient loss, throughevaporation or degradation, or due to chromatographic effects, by whichis meant the tendency of certain film ingredients to preferentially trapor bind certain flavour ingredients, leading to a perceived imbalance ofthe flavour delivered to the consumer.

By sequestering active agent from the film-forming material in this way,the invention also enables high loading of active agent without causingany deleterious effects on film stability, such as mechanical stability,hygroscopic stability and the like.

Microcapsules may be employed to contain colourants. It has proven to betechnically difficult to introduce colours, and in particular,combinations of colours into an edible film without colours leaching outof their assigned configurations during manufacture and during prolongedperiods of storage. Employing pre-coloured populations of microcapsulesprovides a simple means of colouring films effectively, even withintricate designs. Furthermore, because they are encapsulated, thecolours display a considerably reduced tendency to leach or diffuse overtime. Notwithstanding that colourants may be introduced into the filmsby means of encapsulation, it is not precluded to add colour to filmsusing conventional means such as over-printing a film using conventionalprinting techniques.

Finally, microcapsules can be used to added additional visual impact tothe edible film of the present invention by using microcapsulepopulations having different diameters to give an impression ofparticulate matter in the film.

Microcapsules my comprise up to about 50 wt % of the composition basedon dry weight, more particularly 20 to 50% by weight. Active agentloading may be in the range of 10 to 50% by weight of the microcapsules.

All manner of encapsulation technologies may be applied in the presentinvention. The particular encapsulating medium used will depend upon thenature of the material to be encapsulated, the desired release kineticsand release profile. Apprised of these factors, the skilled person wouldnot have to resort to inventive activity to select a suitableencapsulating medium to achieve a desired result.

Encapsulation techniques suitable in the present invention includespray-drying, complex coacervation, phase separation techniques (bothaqueous and organic phase separation), cyclodextrin molecularencapsulation, yeast-cell encapsulation, in-situ polymerisation,coating, and extrusion.

Spray drying techniques are well known in the art, and can be used bythe skilled person to form suitable microcapsules for use in the presentinvention. In a typical spray-drying technique, an active agent, usuallyin the form of an oil or in non-aqueous solution is dispersed in anaqueous phase containing film-forming agent to form an emulsion that isfed into a drier through a nozzle that disperses the emulsion into smalldroplets. The drying conditions are chosen depending on a number offactors relating to desired product characteristics and particle sizedesired. All manner of film-forming agents may be employed, for examplethe film-forming carbohydrates, polypeptides and synthetic polymersrecited above as being useful edible film forming materials can beemployed.

Coacervation is a technique well known in the art and involves the stepsof forming a hydrophobic core material containing active agent andemulsifying this in a charged, water-soluble polymer solution having theproperties of a protective colloid. Thereafter, an oppositely chargedhydrophilic colloid solution is added thereto. Process conditions suchas colloid concentration, pH and temperature are controlled to inducephase separation (coacervation) to precipitate a colloid-rich coating ofthe polymer onto the hydrophobic active-containing core to form amicrocapsule wall. The wall is thereafter hardened and renderedinsoluble by crosslinking using suitable cross-linkers such asaldehydes, e.g formaldehyde. Materials for use in the capsule wall arewell known in the art and include proteins such as gelatin, orfilm-forming carbohydrates as aforementioned such as alginates.

Encapsulation by extrusion can proceed by making a melt of a matrixmaterial, or a solution of matrix material and co-extruding this with anactive agent, using a screw extrude or the like, before drying, orcooling, and grinding to form microcapsules. Matrix material may beformed of a hydrophilic and glassy material such as a water-solublesugar or sugar mixture. Such matrices are typically impervious tomoisture and oxidants and are useful to encapsulate oxidation- andmoisture-sensitive active agents. Alternatively, matrix materials may behydrophobic, such as a vegetable fat, edible waxes, or film-formingcarbohydrate, or even mixtures of hydrophobic and glassy-hydrophilicmaterials; the combinations of materials being selected to achieve aparticularly desired delivery effect, having regard to the active agent.

Particles of active agent may also be coated with encapsulating media ofany of the film-forming materials referred to herein above. Coatingtechniques may be used to coat particles, usually solid particles, ofactive agent, or even may be used to further coat encapsulated formsdescribed herein above.

Coating may be carried out according to known techniques such as spraycoating, pan coating, fluid bed coating, rotogranulator coating, annularjet coating, spinning disk coating, spray cooling, spray drying,filtermat drying, Multi Stage Drying (MSD) drum roll coating, freezedrying, and spray chilling.

The skilled person will appreciate that the particular technique usedand the encapsulating material employed will depend upon the nature ofthe active agent to be encapsulated and the type of releasecharacteristic that is sought to be achieved. For example when aflavouring agent is employed that contains a flavourant aldehyde it ispreferred not to employ an encapsulating material that contains apolypeptide such as gelatin, as the aldehyde will act to crosslink thepolypeptide over prolonged periods of time and this may effect the filmsability to hydrate and dissolve, or disperse rapidly when placed, forexample, in the mouth. Furthermore, if food acids are employed in anencapsulating media, the encapsulating media preferably contains fattysubstances such as edible waxes, and vegetable fats and the like, orsome other medium that efficiently encapsulates acids preventing themfrom leaching into the film.

The edible film as herein above described may be prepared according to aprocess comprising the steps of preparing an aqueous solution of thefilm-forming materials, food acid and other optional excipients oractive agents as herein above described; mixing the solution untilhomogenous, and optionally adding microcapsules comprising active agent,and/or food acid; casting the resultant mixture onto a releasablebacking media; coating the mixture, for example using conventionalknife-coating techniques; and drying the film.

The drying operation may be carried out in a high-temperature air-bath,drying tunnel, vacuum drier, or any other suitable method.

Encapsulation may be employed to encapsulate thermally sensitive agentsthereby to permit processing at high temperatures, e.g. up to 90° C. toreduce processing time, without substantially affecting the retention ofthe active agents or their integrity.

The edible film of the present invention may have a papery, wafer-likeconsistency that is possessed of sufficient mechanical strength to behandled without special precautions. The film may be provided incontinuous sheets that may be rolled onto spools, or cut into sheets andstacked for storage. The films may be cut into any desirable shape forthe particular intended end use, and packed in suitable containers.

The thickness of the films can be precisely controlled during themanufacturing process to vary, for example between 5 and 200 microns.The film may be a mono- or multi layer construction. In the case of amonolayer film, microcapsules may be dispersed throughout a monolayer ofthe film-forming material. If the edible film is in the form of amultilayer, it may comprise a discrete layer consisting of themicrocapsules, in addition to the layer of film-forming material. Thediscrete layer may be formed according to any suitable process, e.g.microparticles may be sprayed or sprinkled onto a wet film before itpasses through a drying process.

When placed directly in the mouth, the edible film is quickly hydratedand is softened and develops mucoadhesive properties; thereafter itdisperses or dissolves rapidly in the oral cavity, e.g. within about 30seconds and so does not feel obtrusive or leave an unpleasant mouthfeel.

A further advantage of employing microcapsules is that despite the filmdissolving or dispersing rapidly in the mouth the microparticles lingerin the oral cavity so creating a prolonged release of active agentwithout attendant adverse mouth feel. One is therefore able to effect along-lasting taste, or pharmaceutical effect, e.g. 20 minutes or morewithout attendant adverse mouth feel. In existing commercial products,once the film has dissolved such that there is no longer any unpleasantmouth feel, the flavour sensation or the cosmetic or pharmaceuticaleffect is lost relatively rapidly thereafter as the active agent isquickly washed away by saliva. The microcapsules, in contrast, areretained in the oral cavity for longer time periods by being physicallytrapped in pits or fissures in the oral tissue, or by possessing certainmucoadhesive properties similar to those of the film.

There now follows an Example that serves to illustrate the invention.

EXAMPLE 1

A formulation containing fruit flavours and food acid was formedaccording to the following methodology. Wet Wt Dry Wt Deionised Water582.7 Pure Coat 792 Modified Starch 20 20 HPMC 35 35 Gelatin 97 97Polysorbate 80 10 10 Glycerine 20 20 Sodium Saccharine 5 5 FDC Red 40Lake 0.3 0.3 Malic acid 50 50 Cherry Emulsion 130 48.1 CherryEncapsulated 50 50 TOTAL 1000 335.4

A solution was made of the cherry flavourant in water. This solution wasmixed with the encapsulating agent (Flavorburst® Dry Protein Encapsulate(Givaudan)) for 30 minutes. The Flavourant was absorbed intoFlavorburst® after 30 minutes and a dry encapsulated powder was formed.

A solution of starch was made by adding water to the starch and mixingwith high shear until a clear solution was formed.

A solution of gelatin was made by heating deionised water to 70 degreescentigrade and adding slowly with stirring fish gelatin. The solutionwas cooled to 30 degrees.

A coating solution was formed by mixing the aforementioned solutionsbefore mixing in the encapsulated flavourant and emulsifier, colourantand additional flavourant. Mixing was carried out until no lumps werepresent.

This coating solution was coated onto a polyethylene coated differentialrelease paper using a knife-over-roll coating head. The coated paper wasthen dried in a drying tunnel to form the film. The film has a paperwafer like consistency. The film was then cut into pieces. Pieces werethen tested for sensory response of flavour release in the oral cavity.

The edible film produce was papery, wafer-like in consistency, dry tothe touch and capable of being stored in adjacent layers withoutsticking. When presented to the mouth it imparted an immediatemouth-watering sensation and flavour with the flavour lasting for aperiod of up to 20 minutes.

When the starch and HPMC were replaced with an alginate film-former, itwas not possible to form a good, continuous film. On the contrary, thefilm was blotchy exhibiting streaks of material and holes.

1. An edible film composition for delivering an active agent to the oralcavity, the composition comprising a water-dispersible film-formingmaterial selected from a cellulose ether and a starch, and a food acid.2. A composition according to claim 1 wherein the food acid is selectedfrom the group consisting of citric acid, malic acid, glacial aceticacid, anthranilic acid, tartaric acid, tiglic acid, ascorbic acid,benzoic acid, tannic acid, succinic acid, adipic acid, fumaric acid,lactic acid, and mixtures thereof.
 3. A composition according to claim 1wherein the food acid is present in amounts of at least about 8 wt %based on the dry weight of the composition.
 4. A composition accordingto claim 1 wherein the active agent is selected from a flavourantformulation, a pharmaceutical agent, a nutraceutical agent, or mixturesthereof.
 5. A composition according to claim 1 wherein active agent isencapsulated in microcapsules that are dispersed throughout the film. 6.A composition according to claim 5 wherein the microcapsules comprise afirst population of microcapsules containing a first active ingredient,and a second population of microcapsules containing a second activeingredient.
 7. A composition according to claim 1 additionallycomprising gelatin and or pectin.
 8. A composition according to claim 1in the form of thin wafer.
 9. A composition according to claim 8 whereinthe thin wafer is a monolayer.
 10. A composition according to claim 8having a thickness of 5 to 200 microns.
 11. Packaging comprising aplurality of wafers according to claim 8.